Consider the function f(x,y,z) = xyz-1, the point P(0, -3, -3), and the unit vector u = a. Compute the gradient of f and evaluate it at P. b. Find the unit vector in the direction of maximum increase of f at P. c. Find the rate of change of the function in the direction of maximum increase at P. d. Find the directional derivative at P in the direction of the given vector. - a. What is the gradient at the point P(0, -3, -3)? (Type exact answers in terms of e.) 9 6 11'11'